This particular invention relates generally to film processing and, more particularly, it concerns a method and photographic film cassette having an improved fluid processing applicator system for releasing processing fluid on a strip of traveling film.
Multipurpose film cassettes for use in the motion picture art have been developed in which a strip of photographic film is selectively and sequentially operated to be exposed, processed and projected while at all times remaining in the cassette. Film cassettes of this type are disclosed in several U.S. patents assigned in common with the present invention.
Typically, such cassettes contain a supply of light-sensitive photographic film which is selectively exposable whenever the cassette is in a camera particularly adapted to receive and operate the same. To process or develop the exposed film, the cassette is removed from the camera. Thereafter it is placed in a player or processing and viewing apparatus capable of activating a cassette contained processor for effecting deposition of a processing fluid on the film's exposed emulsion surface as the latter is advancing therepast. During such processing a conventional series of successive, positive transparent images on the exposed film is developed. Following processing as indicated above, the player apparatus is operated as a projector, whereby the film is incrementally advanced, frame-by-frame, past a light source. In this manner, the series of positive transparent images of the scenes to which the film were exposed are capable of being successively viewed while being projected onto a screen.
It is clear that the advance in the motion picture art represented by such a system is apparent and needs no elaboration herein. However, for satisfactory cassette performance it is vital that the processing fluid be timely and effectively released from a cassette contained fluid processor onto the advancing film strip. Otherwise, delays and defects in the delivery of processing fluid may lead to an incomplete and non-uniform coating, thereby adversely affecting achievement of a uniform diffusion transfer on the film strip. It is to be understood that any defect in the processing operation is likely to cause permanent blemishes in the positive image transparencies carried on the film strip. It follows, therefore, that the achievement of effective fluid storage and timely fluid release onto the film strip during processing have been major focal points of attention in overall system development.
The current state of the art with respect to achieving the appropriate release of the processing fluid on such cassette contained film strip is represented by the disclosures of U.S. Pat. No. 3,871,013 issued Mar. 11, 1975 to Edward F. Burke and Douglas B. Holmes; U.S. Pat. No. 3,895,862 issued July 22, 1975 to Joseph A. Stella, Edward F. Burke, Jr. and Paul B. Mason; and U.S. Pat. No. 3,951,530 issued Apr. 20, 1976 to Frank M. Czumak, Paul B. Mason and Joseph A. Stella, all of which patents are commonly assigned with the present invention. In cassettes of the foregoing category, the processing fluid is stored in a closed reservoir or pod positioned within the film cassette. Use is made of a removable tear-tab closure for ensuring releaseable retention of the stored fluid. During the processing mode, the player apparatus activates the processor to cause the removable tear-tab closure to be opened. While the tear-tab closure successfully operates, it requires a relatively sophisticated mechanical cooperation between several cassette contained components. In this regard, the tear-tab is releasably bonded to a reservoir having a relatively large mouth so as to seal completely the opening. To effect removal of the tear-tab for opening the reservoir the former is provided with a folded back portion trained over a guide roller and connected to and movable with a pull strip. Removal commences when a latching tongue of the pull strip engages and moves with an aperture in the leader end of the film during rewinding of the exposed film strip back to the supply spool. Continued rewinding of the supply spool will produce a pulling action on the pull strip. This pull strip displacement is translated into corresponding displacement of the tear-tab, which by virtue of its configuration and connection, will be peeled from the reservoir to thereby enable the processing fluid to flow through a nozzle opening in the processor. Also in systems of this type, it is necessary to separate and store the tear-tab closure from the pull strip so as to avoid the tear-tab hampering the intended operation of the cassette as well as contaminate the strip as a result of contact with any portion of the tear-tab. Towards this particular end, the tear-tab closure is separated by a knife-like formation at the exit of a channel formed by internal cassette walls which walls also form a storage chamber for the separated closure. While the foregoing approach is successful in operation, it nevertheless is reliant upon several mechanical components and connections. This, however, gives rise to potential mechanical problems.
Other systems have been developed for releasing processing fluid from a reservoir housed in a film cassette without the use of a pull strip/tear-strip arrangement. One type of approach, such as described, for example, in U.S. Pat. No. 3,396,650 issued Aug. 13, 1968 to Leon Rubinstein and Arthur J. Sable; U.S. Pat. No. 3,344,728 issued Oct. 3, 1967 to Allan B. MacQuarrie and Arthur J. Sable; and U.S. Pat. No. 3,593,643 issued July 20, 1971 to Rogers B. Downey, has been directed to use a rupturable container which ruptures when a mechanical force applying member applies force thereto so as to increase the fluid pressure within the container to a preselected amount. Another approach is described in U.S. Pat. No. 3,767,297 issued Oct. 23, 1973 to Rogers B. Downey, wherein the processing fluid is released upon actuation of a solenoid operated plunger causing breakage of a frangible glass vial housing the fluid.
The novel arrangement as set forth herein is directed to the use of nonmechanical means for rupturing a fluid processing container, and preferably by the application of thermal energy. In this regard, although U.S. Pat. No. 4,047,213 issued Sept. 6, 1977 to Edwin H. Land discloses heating components positioned in the cassette, the heating is only directed to improving the diffusion transfer of photographic films after release of the fluid from the reservoir by a conventional pull strip/tear-tab arrangement.